The following apparatus and procedures were elaborated: (1) an apparatus for the optimization of the pH of PAGE, providing simultaneous analysis at up to 10 pH values; (2) a compact evacuator, providing for controlled removal of oxygen (a polymerization inhibitor) from the polymerization mixture; and (3) an apparatus for automated pH gradient measurement in electro-focusing. BIBLIOGRAPHIC REFERENCES: Bui, C., Galea, V. and Chrambach, A.: An apparatus for the simultaneous performance of polyacrylamide gel electrophoresis at multiple pH. Anal. Biochem., 81:108-117, 1977. Chidakel, B.E., Nguyen, N.Y., and Chrambach, A.: A device for the automated measurement of pH-gradients in gel electrofocusing. Anal. Biochem. 77: 216-225, 1977.